The study was conducted with 3,385 participants who took an English language proficiency test as a partial requirement for entering a PhD program in different fields of education. This test has three sections which are grammar, vocabulary and reading comprehension. To determine the construct validity of the test, a series of analyses were done. Total test items were subjected to a factor analysis assuming three factors. It was seen the three components postulated theoretically were verifiable. In other words, there were three distinct sections in the test. These were grammar, vocabulary, and reading comprehension. Furthermore, the data from the grammar section were subjected to an exploratory factor analysis (EFA). Having conducted EFA through Principal Components Analysis (PCA) with varimax rotation yielded distinct factors in the grammar section. In one sub-section, eight distinct factors and in the other sub-section six distinct factors were extracted. (Contains 3 tables.)